Over twenty thousand lightning location data obtained by using Lightning Location System(LLS) from Lanzhou and Beijing regions have been analysed to ascertain the characteristics of ground flashes in both regions. The...Over twenty thousand lightning location data obtained by using Lightning Location System(LLS) from Lanzhou and Beijing regions have been analysed to ascertain the characteristics of ground flashes in both regions. The strength of positive flashes is 5 times higher in Lanzhou than in Beijing. The strength of positive flashes is 3 times and 2.2 times as large as negative flashes in Beijing and in Lanzhou respectively. It has been found that the strength of positive and negative flashes is submitted to the normal distribution, and is independent of the characteristics of thunderstorm. So the lightning strength obtained by DF may be used to forecast the coming of thunderstorm. Although the stroke number in both regions decreases as exponent regulation, the maximum number of return stroke for one lightning in Beijing is more than that in Lanzhou. The peak flash rate occurs in late afternoon for both regions, but the maximum and minimum flash rate appeared an hour earlier in Beijing than in Lanzhou.The relationship between DF display and lightning radiation electric field, discharge current is obtained.展开更多
The electrical characteristics of thunderstorms in three different altitude regions of the Chinese inland plateau have been analyzed in this paper. The results show, according to the polarity of the surface electric ...The electrical characteristics of thunderstorms in three different altitude regions of the Chinese inland plateau have been analyzed in this paper. The results show, according to the polarity of the surface electric （E） field, that the thunderstorms can be divided into two categories in the study regions： one showing the normal tripole electrical charge structure （normal-type）, and the other showing the special tripole charge structure with a larger-than-usual lower positive charge center （LPCC） at the base of thunderstorm （special-type）, where the induced surface E field is controlled by the LPCC when a thunderstorm is overhead. We find that the two types of thunderstorms have different occurrences in different regions, and the percentage of special-type thunderstorms increases with the altitude. On the whole, the flash rate of thunderstorms is quite low, and the mean value is about 1-3 fl/min, while the flash rate of special-type is slightly greater than that of the normal-type thunderstorm. The statistical results of cloud-to-ground flash （CG） numbers indicate that the ratio of ＋CG flash increases with the altitude, with the value about 14.7 percent through 25.4 percent.展开更多
选用FY-4A卫星闪电成像仪(Lightning Mapping Imager, LMI)数据、闪电定位数据(Advanced Time of Arrival and Direction, ADTD)、常规探空资料、区域自动站资料、多普勒天气雷达与ERA5再分析资料,对2023年7月河北省一次特大暴雨过程的...选用FY-4A卫星闪电成像仪(Lightning Mapping Imager, LMI)数据、闪电定位数据(Advanced Time of Arrival and Direction, ADTD)、常规探空资料、区域自动站资料、多普勒天气雷达与ERA5再分析资料,对2023年7月河北省一次特大暴雨过程的闪电变化特征进行对比分析。结果表明:两种闪电资料的时空分布存在差异,LMI的闪电白天少、夜间多,数量约为ADTD的1/8。降雨分布与闪电密度分布也存在差异,ADTD探测的地闪密度高值区位于河北中东部,累计降水量超过400 mm的区域位于河北西部,强降水分布与35 dBZ以上回波的频次分布相一致。降水强度与闪电频次相关关系不显著,7月29—30日强降水过程的闪电活动不活跃,7月31日至8月1日随回波顶位置升高、冰相层增厚,强降水过程的闪电活动显著增强,闪电分布与45 dBZ以上强回波垂直结构及粒子分布均较为密切。展开更多
文摘Over twenty thousand lightning location data obtained by using Lightning Location System(LLS) from Lanzhou and Beijing regions have been analysed to ascertain the characteristics of ground flashes in both regions. The strength of positive flashes is 5 times higher in Lanzhou than in Beijing. The strength of positive flashes is 3 times and 2.2 times as large as negative flashes in Beijing and in Lanzhou respectively. It has been found that the strength of positive and negative flashes is submitted to the normal distribution, and is independent of the characteristics of thunderstorm. So the lightning strength obtained by DF may be used to forecast the coming of thunderstorm. Although the stroke number in both regions decreases as exponent regulation, the maximum number of return stroke for one lightning in Beijing is more than that in Lanzhou. The peak flash rate occurs in late afternoon for both regions, but the maximum and minimum flash rate appeared an hour earlier in Beijing than in Lanzhou.The relationship between DF display and lightning radiation electric field, discharge current is obtained.
基金supported by National Natural Science Foundation of China (Grant No. 40905001, 40775004)the Main Direction Program of the Knowledge Innovation of Chinese Academy of Sciences (Grant No.KZCX2-YW-206)
文摘The electrical characteristics of thunderstorms in three different altitude regions of the Chinese inland plateau have been analyzed in this paper. The results show, according to the polarity of the surface electric （E） field, that the thunderstorms can be divided into two categories in the study regions： one showing the normal tripole electrical charge structure （normal-type）, and the other showing the special tripole charge structure with a larger-than-usual lower positive charge center （LPCC） at the base of thunderstorm （special-type）, where the induced surface E field is controlled by the LPCC when a thunderstorm is overhead. We find that the two types of thunderstorms have different occurrences in different regions, and the percentage of special-type thunderstorms increases with the altitude. On the whole, the flash rate of thunderstorms is quite low, and the mean value is about 1-3 fl/min, while the flash rate of special-type is slightly greater than that of the normal-type thunderstorm. The statistical results of cloud-to-ground flash （CG） numbers indicate that the ratio of ＋CG flash increases with the altitude, with the value about 14.7 percent through 25.4 percent.
文摘选用FY-4A卫星闪电成像仪(Lightning Mapping Imager, LMI)数据、闪电定位数据(Advanced Time of Arrival and Direction, ADTD)、常规探空资料、区域自动站资料、多普勒天气雷达与ERA5再分析资料,对2023年7月河北省一次特大暴雨过程的闪电变化特征进行对比分析。结果表明:两种闪电资料的时空分布存在差异,LMI的闪电白天少、夜间多,数量约为ADTD的1/8。降雨分布与闪电密度分布也存在差异,ADTD探测的地闪密度高值区位于河北中东部,累计降水量超过400 mm的区域位于河北西部,强降水分布与35 dBZ以上回波的频次分布相一致。降水强度与闪电频次相关关系不显著,7月29—30日强降水过程的闪电活动不活跃,7月31日至8月1日随回波顶位置升高、冰相层增厚,强降水过程的闪电活动显著增强,闪电分布与45 dBZ以上强回波垂直结构及粒子分布均较为密切。
